Caption: Liquid nitrogen. Liquid nitrogen being poured from a flask. This fluid is widely used as a coolant in low-temperature research & for storing biological samples. The vapour around the mouth of the flask is made of water droplets condensed from the air by the extremely low temperature. Liquid nitrogen boils at a temperature of -195.8 degrees celsius. About 78% of the Earth's atmosphere is nitrogen. Nitrogen is fairly unreactive at room temperatures but can be used to make ammonia, cyanides, calcium cyanamide and nitrogen oxides.